- Nest compositor pages under the compositor module
- Nest GUI, DNA/RNA & externformats modules under Blender.
- Remove modules from intern which no longer exist.
- Add intern modules (atomic, eigen, glew-mx, libc_compat, locale,
numaapi, rigidbody, sky, utfconv).
- Use 'intern_' prefix for intern modules since some of the modules
use generic terms such as locale & atomic.
This was using TreeElement before it was fully defined, which gives undefined
behavior that happened to work with other libraries but not libc++.
Based on patch by Marcus von Appen, modifications for brevity and to ensure we
don't dereference invalid memory. Ref T37477.
